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May 15, 1999
 ---Disc
edema in a patient with thyroid optic neuropathy and field
defect.
WAIKOLOA, Hawaii — Smoking and radioactive iodine treatment alone are
two risk factors for developing thyroid optic neuropathy among patients
with Graves’ hyperthyroidism.
“We now know that smoking is a significant risk factor,” said Robert L.
Lesser, MD, a neuro-ophthalmologist in private group practice in
Waterbury, Conn. “This is another reason to warn these patients that they
should not be smoking. In fact, patients who have thyroid disease in
general are seven times more likely to develop a more severe form of
ophthalmopathy if they smoke.”
![[bar]](on_and_smoking_files/gradient.gif)
Combined
treatment may be better
 ---Clinical
photograph of a patient with marked limitation of gaze with
thyroid optic neuropathy and minimal proptosis.
Radioactive iodine treatment alone also increases the risk of
contracting or worsening ophthalmopathy. One study published last year
showed that 15% of patients who were treated only with radioiodine
developed or had worsening ophthalmopathy. In contrast, none of the
patients who were treated with both radioiodine and prednisone had
progression, and two-thirds showed improvement. Further, only 3% of those
treated with methimazole had any worsening of eye disease.
“Presumably what happens with thyroid ophthalmopathy is that the
lymphocytes that are targeting against the thyroid also react to the eye
muscles. You end up with lymphocytic infiltration and mucin deposition,”
said Dr. Lesser, who spoke here at Hawaii ‘99, sponsored by Ocular
Surgery News and the New England Eye Center.
The inferior rectus, medial rectus and superior rectus are the most
commonly involved muscles, “so it is really an eyeball diagnosis,” said
Dr. Lesser, who recommends “a computerized tomography [CT] scan or
magnetic resonance imaging [MRI] of the orbit with fat suppression to
document enlargement of the muscles.”
Dr. Lesser cited a female patient with white eyes. “That doesn’t
necessarily make a difference, though. Sometimes the eyes are congested
and sometimes they are not,” he said. However, the patient also had
minimal proptosis. “That is one of the tip-offs that there is a greater
risk for thyroid optic neuropathy, be cause of the simple mechanical
crowding phenomenon.”
Although the risk of developing the disease is relatively low (1% to
5%), vision loss is possible; therefore, these patients should be tested
and followed closely. Moreover, the absence of disk edema does not exclude
the diagnosis.
Test useful
for early detection
  ---A CT and MRI of a patient with enlarged
muscles secondary to thyroid optic neuropathy.
Visual-field and color-vision testing help in early detection.
“Patients need to be alerted about the possibility of a change in vision
and need to arrange to see you if this happens,” Dr. Lesser said. Low-dose
radiation may be appropriate for even some of the congestive findings.
Once the diagnosis is made, Dr. Lesser starts patients on short-term
steroids. “I do not favor using steroids on a long-term basis because I
think the treatment becomes worse than the disease,” he said. He also
mentioned that high-dose steroids may be appropriate in certain
situations. “We are now becoming comfortable with 1 g of
methylprednisolone intravenous for 3 to 5 days and seeing if that rapidly
decompresses the muscle.”
Dr. Lesser’s patients are maintained on steroids throughout radiation
treatment. “It is at that point that I taper the steroids and then measure
the effect,” he said. “Results are quite good in most cases.” Surgical
decompression of the orbit is reserved for those patients with a
contraindication or intolerance. “You have several choices with
decompression, including lateral wall, medial wall and inferior wall,” he
said.
Overall, patients are “psychologically devastated” by thyroid
orbitopathy, Dr. Lesser said. “A lot of these patients need counseling and
support.”
For Your Information:
- Robert L. Lesser, MD, can be reached at 1201 W. Main St.,
Waterbury, CT 06708; (203) 597-9100; fax: (203) 597-1696. Dr. Lesser
has no direct financial interest in any of the products mentioned in
this article, nor is he a paid consultant for any companies mentioned.
Reference:
- Bartalena L, Marcocci C, Bogazzi F, et al. Relation between
therapy for hyperthyroidism and the course of Graves’ ophthalmopathy.
N Engl J Med. 1998;338(2):73-78.
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